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Heart rate changes during positive pressure ventilation after asphyxia-induced bradycardia in a porcine model of neonatal resuscitation
  1. Maria Liza Espinoza1,2,
  2. Po-Yin Cheung2,3,
  3. Tze-Fun Lee2,3,
  4. Megan O’Reilly2,3,
  5. Georg M Schmölzer2,3
  1. 1Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
  2. 2Centre for the Studies of Asphyxia and Resuscitation, Royal Alexandra Hospital, Edmonton, Alberta, Canada
  3. 3Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
  1. Correspondence to Dr Georg M Schmölzer, Neonatal Research Unit, Centre for the Studies of Asphyxia and Resuscitation, Royal Alexandra Hospital, Edmonton, AB T5H 3V9, Canada; georg.schmoelzer{at}


Background The Neonatal Resuscitation Program (NRP) states that if adequate positive pressure ventilation (PPV) was given for a low heart rate (HR), the infant’s HR should increase within the first 15 s of PPV.

Objective To assess changes in HR in piglets with asphyxia-induced bradycardia.

Methods Term newborn piglets (n=30) were anaesthetised, intubated, instrumented and exposed to 50 min normocapnic hypoxia followed by asphyxia. Asphyxia was achieved by clamping the tube until severe bradycardia (defined as HR at <25% of baseline). This was followed by 30 s adequate PPV and chest compression thereafter. Changes in HR during the 30 s of PPV were assessed and divided into four epochs (0–10 s, 5–15 s, 10–20 s and 20–30 s, respectively).

Results Increase in HR >100/min was observed in 6/30 (20%) after 30 s of PPV. Within the epochs 0–10 s, 5–15 s or 10–20 s no piglet had an increase in HR >100/min. Additional 10/30 (33%) had a >10% increase in HR.

Conclusion In contrast to NRP recommendation, adequate PPV does not increase HR within 15 s after ventilation in piglets with asphyxia-induced bradycardia.

  • newborn
  • infants
  • neonatal resuscitation
  • asphyxia
  • heart rate

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  • Contributors Conception and design: GMS, PYC. Drafting of the article: MLE, GMS, PYC, TFL, MOR. Critical revision of the article for important intellectual content: MLE, GMS, PYC, TFL, MOR. Final approval of the article: MLE, GMS, PYC, TFL, MOR.

  • Funding This study was funded by the Women and Children’s Health Research Institute, Edmonton, Alberta; Heart and Stroke Foundation of Alberta; Heart and Stroke Foundation of Canada; Neonatal Resuscitation Program; and Canadian Paediatric Society.

  • Disclaimer The sponsors of the study had no role in study design, data collection, data analysis, data interpretation or writing of the report.

  • Competing interests None declared.

  • Ethics approval Animal Care and Use Committee (Health Sciences), University of Alberta (AUP00000237)

  • Provenance and peer review Not commissioned; externally peer reviewed.

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